What is the right level of public housing a society should aim for. In the UK we have a relatively high % of public housing aiui, although that is topped by a few, and a much higher % than the EU and OECD averages.
It's a question I don't have a good answer to but depends on many factors and I'm not sure comparisons between countries are always relevant.
eg I suspect a lot would depend on tenant protections and security in the private rental market (including sub-standard properties with eg dangerous damp, poor insulation, etc.). My impression is that the UK "regulations" (or lack of) are primarily in the interests of landlords and their profitability. And even when there are regulations how easy is it for tenants to get those enforced (without being evicted).
If the private rental market is of adequate standard (housing quality, tenant security, pricing, etc.) then I would consider no good reason for Councils to get involved. If there is good quality, etc. available through social housing charities then again no need for Councils.
But my impression is that the rental situation in the UK is not working, has not been working for a long time and Governments have been unable and/or unmotivated to resolve. (Maybe the private market "works" for landlords but often not working for tenants).
Ian